The best way to interpret how the central conflict was resolved in the story is:
The central conflict does not have a resolution with this ending, but rather ends in an ironic way.
This interpretation captures the fact that while Mariko and Felice initially deal with the conflict of breaking the window and agree on a course of action, the resolution is overshadowed by the sudden and destructive arrival of the tornado, which upends the situation dramatically. The irony lies in the fact that the girl's issue with the broken window becomes insignificant in the face of a much larger disaster.